Roller mounted drawing triangle

ABSTRACT

A drawing triangle having a pair of rollers in at least two of the sides, the rollers being mounted perpendicular to the edge of their respective sides. One set of rollers can be lifted from the paper either by having the sides slightly curved or having a pivot pin near the intersection of the sides having the rollers so that pressure applied on one side will cause the other side to lift.

United States Patent 1 Middelbeek July 24, 1973 [54] ROLLER MOUNTEDDRAWING TRIANGLE 2,066,384 1/1937 Niethammer 33/109 Inventor: Cornelis GMi bee ootdorp 2,800,720 7/1957 Kristlansen 33/109 Netherlands 731Assignee: William Charles Coombs, Primary Examiner-Louis PrinceBuckinghamshire, England Assistant Examiner-Charles E. PhillipsAttorneyStevens, Davis, Miller & Mosher [22] Filed: Dec. 22, 1970 [21]Appl. No.: 100,700

[57] ABSTRACT [30] Foreign Application Priority Data Dec. 23, 1969Netherlands 699309 A drawing triangle having a pair of rollers in atleast two of the sides, the rollers being mounted perpendicu- [52] US.Cl. 33/109 lar to the edge of their respective sides. One set of roll-[51] Int. Cl B43l 13/02 ers can be lifted from the paper either byhaving the [58] Field of Search 33/109, 104 sides slightly curved orhaving a pivot pin near the intersection of the sides having the rollersso that pres- [56] References Cited sure applied on one side will causethe other side to lift.

UNITED STATES PATENTS 630,923 8/1899 Palmer 33/109 7 Claims, 6 DrawingFigures PAIENIEDMZWB 3.747. 211

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Fzgz 5 s B 1 I ROLLER MOUNTED DRAWING TRIANGLE The invention relates toa device for drawing, cutting, tracing, or similar purposes, having twosides which are perpendicular to one another and are interconnected atone end, each side being provided with two substantially cylindricalrolls which are spaced apart and project at least partly from the bottomface of the device.

Such a device, known as a drawing triangle, is disclosed in US Pat. No.2,752,685 of July 3, 1956 or Austrian Pat. No. 170,838. With thetriangle of the prior art, each side carries a long axle provided with acylindrical roll at each end thereof, with the rotary axis of each rollbeing parallel to the corresponding side of the triangle. Such atriangle as known in the art is designed for drawing a number ofparallel lines as is required, for instance, when hatching a drawing.

In order to laterally displace one of the sides to a position which isparallel to itself, that side is subjected to a load in such a mannerthat the triangle will start to perform a tilting motion, causing therolls of the other sides to be raised from the plane of the paper.

It is an object of the present invention to provide a device which whichat least both sides which are perpendicular to one another each may bedisplaced lengthwise over a flat surface as a mobile ruler, the fiatsurface being the plane of the paper where a drawing triangle isconcerned.

This object is achieved by the fact that the two rolls of each side aresupported about two parallel axles which are perpendicular to the edgeof the side upon which they are mounted. The triangle is provided withmeans which cause one side to rise or at least unload when one of theother sides is pressed against a flat surface.

In this manner, lines may be extended in a simple manner by pressing therelative side against the surface as with any conventional triangle.

Upon performing this entirely natural movement, the rolls of theinoperative side are raised from the surface, or at least are unloaded,so that they are prevented from interfering with the parallel guide ofthe side pressed downwardly.

Said raising or unloading of the inoperative rolls may be achieved bydifferent provisions in the device, two of which are illustrated in thedrawing, by way of example, for a drawing triangle.

In the drawing:

FIG. 1 is a top view showing a first embodiment of a drawing triangleaccording to this invention;

FIG. 2 shows a detailed side view along the arrows lI-.II in FIG. 1 atan enlarged scale, in unloaded condition;

FIG. 3 shows the same detailed side view as FIG. 2, but in a loadedcondition;

FIG. 4 shows a top view of a drawing triangle according the a secondembodiment of this invention;

FIG. 5 shows a detailed side view along the arrows V-V in FIG. 4 at anenlarged scale, in unloaded condition, and

FIG. 6 shows the same detailed elevational view as FIG. 5, but in aloaded condition.

The triangle according to FIGS. 1, 2 and 3 comprises mutuallyperpendicular sides 1 and 2 and hypotenuse 3. Usually such a drawingtriangle is made of a relatively rigid, transparent plastic material.

Each side 1 and 2 is provided with two rectangular recesses 4, part of acylindrical roll 5 extending through each said recess. Each roll 5 isrotatable about an axle 6, the ends of which are secured in bearings 7,which are provided on the upper surface of the triangle. The arrangementis such that the axles 6 are perpendicular to the length of thecorresponding side. Each roll 5, which may be manufactured of plastic ormetal, may also be provided with a stationary axle 6, the ends of which,in this instance, may be rotatably supported in the bearings 7. Eachroll 5 is preferably provided with longitudinally extending grooves.Each roll 5 may be replaced by two disc-shaped wheels, spaced apart overa short distance on the same axle. In this instance the dual wheels willact as a cylindrical roll. Alternatively, each roll, farthest removedfrom the right angle, may be replaced by a disc-shaped wheel, providedthe other rolls or dual wheels are retained.

The bearings 7 abut two opposed sides of the rectangular recess 4. Eachroll 5 projects over a short distance from the underside of thetriangle, in a conventional drawing triangle this projection beingapproximately in the order of 1 mm. Accordingly, the triangle rests withfour rolls 5 on the plane of the paper, which is identitied in FIGS. 2and 3 by reference numeral 8.

It will be apprent that if the sie 1, for instance, is moved lengthwiseacross the plane of the paper 8, the rolls of the side 2 will interferewith the movement, because they are only adapted to perform a rollingmovement in one direction.

This problem is solved in the first embodiment by providing each side 1and 2 with a predetermined fixed, upward curve in its middle, that isbetween the rollers, see FIG. 2. This curve may be fixed in variousways. One wayis illustrated in the drawing, viz. with the aid of an astrip 9 having a concave underside. This strip is less deformable thanthe side to which it is secured and preferably consists of transparentplastic as well, so that the view of the plane of the paper under thetriangle is hardly obstructed.

By glueing or welding such a strip 9 having a concave underside on thesides 1 and 2, both sides are slightly curved upwards between therollers. It is understood that the strips 9 may form an integral part ofthe triangle, too.

The vertices of the triangle, in unloaded condition of the triangle, arethus nearer to the plane of the paper 8 than the parts of the sidesbetween the rolls. The strips 9 substantialy' extend over the wholedistance between the rolls.

The fixed curve may even be chosen so large that the triangle, in anunloaded condition, does not rest on the four rolls, but on the ends ofthe sides thereof.

When pressure is exerted from above on the strip 9 of the side 1 againstthe plane of the paper 8, the part of said side between the rolls willmove towards the plane of the paper 8. Inasmuch as the rolls 5 are fixedpressure points, the right side I, initially curved upwards, isstraightened out, see FIG. 3. By having moved the ends of the side 1 inthe upward direction, the whole side 2 is consequently raised, causingthe rolls 5 of the side 2 to be raised from the plane of the paper, orat least to be unloaded to such an extent, that they will no longerinterfere with the moving of the rolls 5 of the side 1.

Furthermore, it is possible to provide the sides 1 and 2 with a fixedcurve without using an aid, such as the strip 9. However, fatigue of theplastic material may cause the curve to become lost and as a consequencethe proper functioning cannot be assured.

If the initial curve of the sides is omitted, satisfactory functioningis not achieved, because it is necessary that the rolls project fromunderneath the triangle only a slight distance, otherwise accuratedrawing along the triangle would be out of the question. Consequently,the vertices are not raised enough if pressure is exerted between therolls; also material fatigue is an additional unfavorable factor.

The triangle shown in the FIGS. 4, 5 and 6 substantially correspondswith the triangle shown in the FIGS. 1, 2 and 3, accordingly only thepoints of difference will be described hereinafter.

This embodiment apparent particularly designated for side largetriangles. The sides are not provided with an initial curve. The strips9, if present, may therefore have straight undersides. With thisembodiment use is made of a pin 10 which is secured to the underside ofthe triangle in the proximity of the inner side of the right angle. Theprojecting end of the pin 10 is slightly rounded, so that littlefriction occurs when the pin slides across the drawing paper. The lengthof the pin 10 is slightly greater than the distance which the rolls 5project from the underside of the triangle. Thus, the flat triangle, inunloaded condition, is supported by the pin 10 and by the rolls 5 whichare farthest removed from the pin 10.

If pressure is exerted on the strip 9 of the side 1, for instance, theroll 5 of the side 1 nearest to the pin 10 will move towards the planeof the paper 8. As the length of the pin 10 is greater than theprojection of the roll, the side 2 is raised with the pressure point ofthe pin 10 on the plane 8 as a tilting point. Thus, the rolls 5 of theside 2 are raised from the drawing paper 8, or are at least unloaded andthe triangle may be moved in the longitudinal direction of the side 1.

Accordingly, with the aid of the triangle of this invention, long linesmay be drawn without utilizing a drawing machine. Hatching can be doneby exerting pressure on the side not used for drawing.

The great advantage of this triangle is that it may be used without thedraftsman having to perform any different movements from those he isaccustomed to perform.

This triangle will be particularly useful in locations where there is noelaborate drawing machine with parallel guide available. Nevertheless,the draftsman has a complete drawing instrument at his disposal, whichmay be taken along wherever he goes.

lt will be apparent thta the invention is not limited to an isosclestriangle having two angles of 45. A 60 right triangle may also beconstructed according to this invention. The hypotenuse may even becompletely omitted so that the device only comprises two rulers inperpendicular relation to each other, these rulers being interconnectedat one end.

The hypotenuse of the triangle may be provided with a set of rolls aswell, although in practice there will be little need therefor.

Although this device has been described above for use in a draftingoffice, it will be apparent that it may also be used for cutting,tracing or marking out workpieces in a machine shop. To this end, eachside may be provided with a stylus or knife 12 (see FIG. 1) disposed inan approximately central position between the rolls, this stylus orknife projecting from underneath the device a distance approximatelyequal to that of the rolls. If, in that instance, pressure is exerted ona side, the stylus or the knife will follow the downward movement.

If desired, the stylus or knife may be subjected to an additional amountof pressure by employing resilient means. With this a deeper cut may beachieved or a more uniform pressure if slight irregularities are met inthe surface to be cut or to be provided with lines.

By using a pen or pencil instead ofa stylus, the resulting triange maybe used for making drawings. In that instance, upon moving the trianglea long pencilled or inked line will automatically be produced.

The foregoing description is given by way of example only and it shouldbe understood that the scope of the invention is defined only by thefollowing claims.

What is claimed is:

1. A marking guide comprising two arms which are perpendicular to oneanother and interconnected at one end, each of said arms being providedwith two substantially cylindrical rolls which are spaced apart andproject at least partly beneath the bottom surface of the guide, the tworolls of each arm being supported on two parallel axles, said axlesbeing mounted substantially perpendicular to the edge of the arm uponwhich they are mounted, means to at least unload the rolls of one sidewhen the other side is pressed toward a flat surface upon which thedevice is resting, said means being an upward curve of at least one arm,between the rollers of that arm.

2. The of claim 1 in which the curve is fixed by a strip secured to anarm, said strip being less deformable than the arm to which it issecured and having substantially the same length as the distance betweenthe two parallel rolls, said strip having a concave surface secured tothe upper surface of an arm.

3. The guide of claim 2 in which a strip is fastened to each arm byglueing or welding.

4. The guide of claim 2 in which each strip forms an integral part ofthe device.

5. Tl-le guide of claim 1 in which on at least one arm, at a pointbetween the rolls, a marking point extends from the underside of thedevice about the same distance as the rolls extend.

6. A marking guide comprising a right triangle, each of the armsadjacent the right angle having a pair of rollers, each roller mountedfor rotation on an axle which is perpendiculr to the edge of the arm, anopening under each roller so that the roller can project through the armto contact a flat surface upon which the device may rest, each said armhaving a slight upward curve at its center portion so that when thatportion is pressed toward said flat surface the pair of rollers on theother arm will be lifted sufficiently to permit the pressed arm to bemoved longitudinally.

7. A marking guide comprising two arms which are perpendicular to oneanother and interconnected at one end, each of said arms being providedwith two substantially cylindrical rolls which are spaced apart andproject at least partly beneath the bottom surface of the guide, the tworolls of each arm beng supported on two parallel axles, said axles beingmounted substantially perpendicular to the edge of the arm upon whichthey are mounted, means adapted to at least unload the rolls of one sidewhen the other side is pressed toward a flat sufrace upon which theguide is resting, said means being a pin disposed in the proximity ofthe inner side of the right angle between the two arms, said pinprojecting from underneath the device to a slightly greater extent thanthe rolls, and serving as a tilting point if one of the arms between therolls is pressed downwardly.

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1. A marking guide comprising two arms which are perpendicular to oneanother and interconnected at one end, each of said arms being providedwith two substantially cylindrical rolls which are spaced apart andproject at least partly beneath the bottom surface of the guide, the tworolls of each arm being supported on two parallel axles, said axlesbeing mounted substantially perpendicular to the edge of the arm uponwhich they are mounted, means to at least unload the rolls of one sidewhen the other side is pressed toward a flat surface upon which thedevice is resting, said means being an upward curve of at least one arm,between the rollers of that arm.
 2. The of claim 1 in which the curve isfixed by a strip secured to an arm, said strip being less deformablethan the arm to which it is secured and having substantially the samelength as the distance between the two parallel rolls, said strip havinga concave surface secured to the upper surface of an arm.
 3. The guideof claim 2 in which a strip is fastened to each arm by glueing orwelding.
 4. The guide of claim 2 in which each strip forms an integralpart of the device.
 5. THe guide of claim 1 in which on at least onearm, at a point between the rolls, a marking point extends from theunderside of the device about the same distance as the rolls extend. 6.A marking guide comprising a right triangle, each of the arms adjacentthe right angle having a pair of rollers, each roller mounted forrotation on an axle which is perpendiculr to the edge of the arm, anopening under each roller so that the roller can project through the armto contact a flat surface upon which the device may rest, each said armhaving a slight upward curve at its center portion so that when thatportion is pressed toward said flat surface the pair of rollers on theother arm will be lifted sufficiently to permit the pressed arm to bemoved longitudinally.
 7. A marking guide comprising two arms which areperpendicular to one another and interconnected at one end, each of saidarms being provided with two substantially cylindrical rolls which arespaced apart and project at least partly beneath the bottom surface ofthe guide, the two rolls of each arm beng supported on two parallelaxles, said axles being mounted substantially perpendicular to the edgeof the arm upon which they are mounted, means adapted to at least unloadthe rolls of one side when the other side is pressed toward a flatsufrace upon which the guide is resting, said means being a pin disposedin the proximity of the inner side of the right angle between the twoarms, said pin projecting from underneath the device to a slightlygreater extent than the rolls, and serving as a tilting point if one ofthe arms between the rolls is pressed downwardly.